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Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales / Giuma Ahmed El-jilali

DOI (Published version): 10.23889/SUthesis.61505

Abstract

A field survey was conducted of an extensive intertidal population of Pagurus bernhardus at Mumbles Head, S. Wales. Mean densities of up to 80 m-2 were observed in a rock pool and locally, higher densities of up to 800 m-2 occurred. There was no evidence of tidal or seasonal migration, or emigration...

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Published: Swansea 1988
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Moyse, John
URI: https://cronfa.swan.ac.uk/Record/cronfa61505
first_indexed 2022-10-10T14:48:12Z
last_indexed 2023-01-13T19:22:17Z
id cronfa61505
recordtype RisThesis
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spelling 2022-10-10T15:52:50.8163531 v2 61505 2022-10-10 Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales 2022-10-10 A field survey was conducted of an extensive intertidal population of Pagurus bernhardus at Mumbles Head, S. Wales. Mean densities of up to 80 m-2 were observed in a rock pool and locally, higher densities of up to 800 m-2 occurred. There was no evidence of tidal or seasonal migration, or emigration from the area although there was an influx of large males from the sublittoral during the breeding season. Sublittoral sampling of the species at a depth of 5 metres on a sandy substrate at Oxwich Bay, Gower, revealed a full range of small individuals in that habitat. Comparison of the intertidal and sublittoral samples of hermits occupying Littorina littorea shells revealed differences. Intertidal hermits of given carapace width occupied larger shells and the colour of the integument, the species of epizoites and the pattern of allometry of the major chela were also found to differ. To determine whether these were genetic or phenotypic differences, enzyme electrophoresis of tissue samples from both populations were compared. They proved identical. Laboratory growth experiments confirmed the findings of earlier workers that moult increments are influenced by the size of available gastropod shells. Rearing studies indicated that small hermits observed as late as March must have been recruited the previous year. Growth rate of recruits was followed from field data. Postulated overall growth curves reconstructed from these data indicated a likely longevity of up to three years for intertidal Pagurus bernhardus and five for sublittoral populations. The high reproductive output of the numerous small hermits is facilitated by their precocious puberty. Studies of Diogenes pugilator indicated that this species has stenotopic ecological requirements and can be regarded as a refugial species in its habitat of the lower tidal and shallow sublittoral surf-pounded sands. Unlike P.bernhardus it is tidally and seasonally migratory so does not have separated populations. E-Thesis Swansea 1 2 1988 1988-02-01 10.23889/SUthesis.61505 COLLEGE NANME COLLEGE CODE Swansea University Moyse, John Doctoral Ph.D 2022-10-10T15:52:50.8163531 2022-10-10T15:45:14.9704240 Faculty of Science and Engineering School of Biosciences, Geography and Physics - Biosciences Giuma Ahmed El-jilali 1 61505__25391__cb3460ac1efd453f9a379242103f24ae.pdf 636782.pdf 2022-10-10T15:48:46.3795030 Output 11760468 application/pdf E-Thesis – open access true true eng
title Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
spellingShingle Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
,
title_short Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
title_full Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
title_fullStr Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
title_full_unstemmed Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
title_sort Ecological studies on two species of hermit crabs Pagurus bemhardus (L.) and Diogenes pugilator (Roux) (Crustacea, Anomura, Paguridae) around the Gower Peninsula, South Wales
author ,
author2 Giuma Ahmed El-jilali
format E-Thesis
publishDate 1988
institution Swansea University
doi_str_mv 10.23889/SUthesis.61505
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Biosciences, Geography and Physics - Biosciences{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Biosciences, Geography and Physics - Biosciences
document_store_str 1
active_str 0
description A field survey was conducted of an extensive intertidal population of Pagurus bernhardus at Mumbles Head, S. Wales. Mean densities of up to 80 m-2 were observed in a rock pool and locally, higher densities of up to 800 m-2 occurred. There was no evidence of tidal or seasonal migration, or emigration from the area although there was an influx of large males from the sublittoral during the breeding season. Sublittoral sampling of the species at a depth of 5 metres on a sandy substrate at Oxwich Bay, Gower, revealed a full range of small individuals in that habitat. Comparison of the intertidal and sublittoral samples of hermits occupying Littorina littorea shells revealed differences. Intertidal hermits of given carapace width occupied larger shells and the colour of the integument, the species of epizoites and the pattern of allometry of the major chela were also found to differ. To determine whether these were genetic or phenotypic differences, enzyme electrophoresis of tissue samples from both populations were compared. They proved identical. Laboratory growth experiments confirmed the findings of earlier workers that moult increments are influenced by the size of available gastropod shells. Rearing studies indicated that small hermits observed as late as March must have been recruited the previous year. Growth rate of recruits was followed from field data. Postulated overall growth curves reconstructed from these data indicated a likely longevity of up to three years for intertidal Pagurus bernhardus and five for sublittoral populations. The high reproductive output of the numerous small hermits is facilitated by their precocious puberty. Studies of Diogenes pugilator indicated that this species has stenotopic ecological requirements and can be regarded as a refugial species in its habitat of the lower tidal and shallow sublittoral surf-pounded sands. Unlike P.bernhardus it is tidally and seasonally migratory so does not have separated populations.
published_date 1988-02-01T20:16:11Z
_version_ 1821347332227072000
score 11.04748

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